Embodiments of the invention relate generally to insulating compositions, and in particular to insulating compositions for use in high voltage devices.
Conventional insulation used in products such as motors and generators typically include several components, such as enamel, tapes, and resin. As such, conventional insulation tends to be a complicated system. Further, each of the constituent components is expected to exhibit different electrical, thermal, and mechanical properties, making overall insulation performance difficult to predict.
One of the major performance parameters is being monitored is the partial discharge magnitude. Partial discharges largely tend to occur at structural defects such as voids, delaminations, and cracks in the insulation. The partial discharges in these defects are caused by the lower dielectric constant at the defects due to the presence of air, compared to that of the surrounding solid insulation materials. The lower dielectric constant leads to a higher impedance and voltage in the localized defect region, and hence leads to partial discharges. Consequences of such partial discharges include changes in the chemistry due to oxidation or carbonization and subsequently treeing, cracking, and eventual catastrophic failure of the insulation.